C.4 Weighing of Evidence
28 ASIC did not adduce any expert evidence in support of its position, although aspects of the expert material adduced by the CBA were challenged by way of cross examination.
29 The primary issue that falls for the Court to decide is the weight to be given to the evidence. ASIC submits that the conclusions to be drawn from the Expert Reports ought to be given little, if any, weight for the following two reasons.
30 First, ASIC submits that the assumptions upon which the expert evidence is based are pitched at a level of generality that provides little insight to the current matter. At the hearing, speaking broadly, the cross-examination was directed to the information provided to the experts and the assumptions that made up the foundations of the Expert Reports. The unanimous answer provided by all three witnesses was that their opinions were founded on the assumption that the users of the CommBank App would be representative of the general population: see T16.30-38, T21.16-25, T28.5-20. Consequently, data specific to the users of the CommBank App was not used to inform the Expert Reports.
31 ASIC submits that the Expert Reports provide no insight into how the users of the CommBank App itself might react, but rather, how the general public might react to receiving a notification containing the Misconduct Notices. However, although one might have thought that more specific material would have been given to the experts as to the cohort of the population that uses the CommBank App, on the evidence as it stands, I am not convinced it matters a great deal. Given that there are 6.3 million users of the CommBank App, in the absence of any other evidence, it is reasonable to proceed on the basis that this is a sufficiently large and generic cohort to justify the assumption that it is broadly reflective of the general public.
32 So much was the evidence of the expert witnesses. For instance, the evidence of Professor Hiscox in re-examination was as follows (at T16.30-35):
[MR KULEVSKI]: … Did you draw any conclusions from the fact that there was 6.3 [million people] using the app about their backgrounds? --- Yes. I … believe this is a fairly, you know, large and representative sample of the Australian population. … I probably should have mentioned from our previous research, we - we had surveyed some of the - of the customers who - who used the app, and we had some information from that survey sample of education levels and sociodemographic information, and it seems to be a very representative sample of the Australian population, and so we can draw some inferences there about likely average education levels, likely average financial literacy levels as well.
33 This evidence was similar to that of Professor Newell and of Ms Guthrie. Mr Newell's evidence (at T25.1-25.4) was as follows:
[MR KULEVSKI]: Did you draw any conclusions about [the fact there were 6.3 million active users of the CommBank App]? --- That that would be a fairly broad and representative proportion of the population throughout which you might expect distributions of different characteristics, individual characteristics.
34 Ms Guthrie shared the same opinion (at T28.5-8):
[MR KULEVSKI]: And what you've done is you've assumed that app users are essentially, users of the CommBank app are essentially representative of the general population? --- I think that's a reasonable, a very reasonable assumption to make. If there are six-point-three million users of the app, that's a very expansive - it's a very good sample size.
35 During the hearing, Ms Guthrie also said that, while it may require a degree of competency and understanding, the use of a smartphone is "an essential item to participate in society today", so much so that "the one thing that a homeless person will have is … a phone because it's the only way you can stay in contact with anyone": T29.19-23.
36 Given the evidence provided by the expert witnesses, the lack of evidence to the contrary, and the sheer size of the cohort, I am willing to find, at a level of generality, that the assumption that the 6.3 million users of the CommBank App would be broadly representative of the general population does not diminish the weight to be given to the evidence of the expert witnesses.
37 Secondly, ASIC submitted that the CBA's failure to adduce specific evidence as to the users of the CommBank App is consistent with the CBA having failed to discharge an evidentiary onus that there would be real difficulties in the use of the CommBank App as proposed by ASIC. Under cross-examination, Professor Hiscox gave evidence as to the level of empirical data upon which he based his opinions expressed in the Hiscox Report. For instance, Professor Hiscox gave the following evidence (at T11.11-29):
[MR LUXTON]: Just so we can understand your insight into the app, do you … know how many notifications are published a day to the average customer that you've referred to? --- I do not. No. I do not.
Do you know if CBA measures and retains that sort of information? --- I believe they would.
Do you know how many items are published on the activity feed per day, again, to the average customer? --- I do not. No. No.
And can I take it that you would expect that CBA would measure and retain that sort of information? --- I would expect so. Yes.
Do you know how many notifications of product offers CBA issues a day, again, to the average customer? --- No, I don't know that.
But, again, you would expect that they would retain - they could measure and retain that sort of information? --- I would expect so.
38 The conclusion that ASIC says the Court ought to draw from the evidence of Professor Hiscox is that the CBA has failed to adduce evidence regarding the specific users of the CommBank App - evidence that, on any rational view, would have assisted the Court.
39 Although not articulated precisely this way by ASIC, the starting point for an examination of the relevance of a failure to call material evidence is the basic principle explained in Blatch v Archer (1774) 1 Cowp 63, as was made clear by the High Court in Australian Securities and Investments Commission v Hellicar [2012] HCA 17; (2012) 247 CLR 345 (at 405-6 [145] per French CJ, Gummow, Hayne, Crennan, Kiefel and Bell JJ).
40 In Blatch v Archer (at 65), Lord Mansfield remarked that "all evidence is to be weighed according to the proof which it was in the power of one side to have produced, and in the power of the other to have contradicted." For present purposes, there is no need to trawl through the principles that are well-known: see Quintis Ltd (Subject to Deed of Company Arrangement) v Certain Underwriters at Lloyd's London Subscribing to Policy Number B0507N16FA15350 [2021] FCA 19; (2021) 385 ALR 639 (at 702 [252], 703 [255]-[256]). To resolve the issue in dispute between the parties, it is sufficient to say that once a fact is put in issue, it "must be decided by a court according to the evidence that the parties adduce, not according to some speculation about what other evidence might possibly have been led": Hellicar (at 412 [165] per French CJ, Gummow, Hayne, Crennan, Kiefel and Bell JJ).
41 ASIC's submission as to the inference to be drawn from the CBA's failure to adduce evidence specific to users of the CommBank App should not be accepted. Given the novel application of s 12GLB contemplated, the assertion that the CBA had access to relevant empirical data is, on the evidence, speculative. Although one may suspect such material exists, there was no attempt by ASIC, by way of a notice to produce or otherwise, to establish that there was specific empirical data held by the CBA prepared for other purposes, which may have been relevant to assessing whether the cohort of users would be confused by the sort of communication contemplated. When prompted, the evidence of Professor Hiscox was (at T8.31-41):
… I did a search myself … because I realised I didn't know whether there had been something like this tested before in the academic … literature where there's a kind of - a warning or a court decision has been reported to a set of customers about the company, and I couldn't find, you know, any published results of a test of something like this. So what the companies have and what's in the marketing literature is - is these personalised offers, or reminders, which again are sort of very different. You know, they're expected in context, you know, the customer expects offers. They expect reminders and calls to action about their particular account.
42 If there was some evidence before me that the CBA had access to a body of research that was relevant to the present issue and decided not to lead it, that failure to lead the evidence might warrant an inference of the kind identified in Blatch v Archer. However, in the present circumstances, no such inference should be drawn.